Development of a Cross‐Conjugated Vinylogous [4+2] Anionic Annulation and Application to the Total Synthesis of Natural Antibiotic (±)‐ABX

Abstract

The cross‐conjugated vinylogous [4+2] anionic annulation has been newly developed, the cascade process of which has a high preference for regiochemical control and chemoselectivity, giving rise to exclusively Michael‐type adducts in moderate to high yields (up to 94 %, 35 examples). By making use of this approach as a key operation, the first total synthesis of natural antibiotic ABX, in racemic form, has been successfully achieved in a concise 7‐step sequence with an overall yield of about 20 %.

Structural derivatization strategies of natural phenols by semi-synthesis and total-synthesis

“…However, catalytic hydrogenation of acrylophenone will preferentially occur at C–C double bond, while the carbonyl could be selectively hydrogenated by sodium borohydride with the addition of CeCl 3 which is known as Luche reduction [ 120 ] (Scheme 13 ). Dehydrogenation of propiophenone fragments always employ 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) as oxidant [ 121 ]. Recently, an efficient, economic and general Pd(OAc) 2 -catalyzed dehydrogenation was developed using molecular oxygen as the oxidant [ 122 ], offering a new option for this transformation.…”

A Convenient Diels-Alder Approach toward Potential Polyketide-like Antibiotics Using α-Activated α,β-Unsaturated 4,4-Dimethyl-1-tetralones as Dienophiles

“…Naturally occurring polyketides isolated from Streptomyces species have an abundance of structural diversities and possess a variety of interesting bioactivities [ 1 , 2 , 3 ]. Among them, a family, featured with a 4,4-dimethyl-1-tetralone unit as highlighted in red in Figure 1 , has been shown to have antimicrobial activities against Gram-positive pathogens, such as methicillin-resistant Staphylococcus aureus ( S. aureus) (MRSA) and vancomycin-resistant S. aureus (VRSA) strains [ 4 , 5 , 6 , 7 , 8 , 9 , 10 ].…”

Enantioselective Synthesis of Fused Butyrolactones via Organocatalytic Formal [2 + 2 + 2] Annulation of γ-Butenolides, Methylene Indolinones, and Nitroolefins

“…As a widely used textbook reaction, the vinylogous addition reaction has played an important role in the total synthesis of natural products . In recent years, it has attracted a lot of interest in the field of asymmetric catalysis .…”